A panel of monoclonal antibodies was prepared from mice immunized with homogenates of ventral forebrain from patients with Alzheimer's disease (AD). The cortex and hippocampus which receive cholinergic innervation from the ventral forebrain have been reported to demonstrate a greater number of neuritic plaques and neurofibrillary tangles. With an enzyme-linked immunosorbent assay (ELISA), two of these antibodies reacted with chloroform/methanol soluble antigens. Folch extraction and partition followed by silicic acid column chromatography revealed the antigens to be glycolipids. Studies with a variety of purified lipids revealed that the antibodies reacted with galactosyl sphingosine, cerebrosides and sulfatides. These antibodies have been used to examine galactosphingolipids in brains with AD with both quantitative ELISA and immunocytochemical techniques. Additionally, the galactolipid composition of Pick's disease has also been studied using these antibodies.